Integrated dual frequency band antenna assembly

Abstract

A radiator assembly has at least one dual frequency band antenna assembly (DFBAA). The DFBAA collocates two isolated frequency band antennas into a single volumetric space. A high-band antenna assembly (aperture and feed structure) is within the same or similar low-band antenna structure while improving gain and field-of-view angular coverage for both bands. There may be quad-ridges that define the low band antenna and a circular waveguide antenna that defines the high band antenna.

What is claimed is: 
     
         1 . A dual frequency band antenna (DFBAA) assembly comprising:
 a radiator including a front end and a rear end, the radiator defining a first antenna at the front end of the radiator, wherein the first antenna is operative at a first frequency range;   a second antenna at the front end of the radiator, wherein the second antenna is operative at a second frequency range that is greater than the first frequency range;   wherein the first antenna is a low band (LB) quadrature ridge (quad-ridge) antenna formed at the front end of the radiator, and the second antenna is a high band (HB) circular waveguide antenna formed at the front end of the body,   a ledge defined by an outer surface of the radiator, wherein the ledge circumscribes the low band (LB) quad-ridge antenna;   a radome having an end that abuts or is closely adjacent to the ledge, wherein the radome covers the LB quad-ridge antenna and the high band (HB) circular waveguide antenna; and   an electrically absorptive ring disposed on the ledge between an inner surface of the radome and the outer surface of the radiator.   
     
     
         2 . The DFBAA of  claim 1 , further comprising:
 a first ridge that is one of four ridges of the LB quad-ridge antenna; and   wherein the first ridge defines a bore, wherein the HB circular waveguide antenna is contained within the bore in the first ridge.   
     
     
         3 . The DFBAA of  claim 1 , further comprising:
 a first ridge that is one of four ridges of the LB quad-ridge antenna; and   wherein the first ridge comprises a convexly curved surface defining a ridge radius that extends from the front end of the radiator to a throat of the LB quad-ridge antenna towards the rear end of the radiator; wherein the ridge radius is flared and sized to position the HB circular waveguide antenna within the first ridge, and wherein the ridge radius is adapted to optimize a high end of the first frequency range.   
     
     
         4 . The DFBAA of  claim 1 , further comprising:
 a primary axis of the radiator extending centrally from the front end to the rear end;   a first ridge that is one of four ridges of the LB quad-ridge antenna;   a second ridge that is one of four ridges of the LB quad-ridge antenna;   a third ridge that is one of four ridges of the LB quad-ridge antenna;   a fourth ridge that is one of four ridges of the LB quad-ridge antenna; and   wherein two of the four ridges are spaced from each other less than 90 degrees relative to the primary axis.   
     
     
         5 . The DFBAA of  claim 1 , further comprising:
 a primary axis of the radiator extending centrally from the front end to the rear end;   a first ridge that is one of four ridges of the LB quad-ridge antenna;   a second ridge that is one of four ridges of the LB quad-ridge antenna;   a third ridge that is one of four ridges of the LB quad-ridge antenna;   a fourth ridge that is one of four ridges of the LB quad-ridge antenna; and   wherein the HB circular waveguide antenna is located between the first ridge and the second ridge.   
     
     
         6 . The DFBAA of  claim 1 , further comprising:
 a cylindrical tube defining a bore of the HB circular waveguide antenna; and   a stepped twist insert within a cylindrical tube of the HB circular waveguide antenna.   
     
     
         7 . The DFBAA of  claim 6 , further comprising:
 a septum disposed within the tube of the HB circular waveguide antenna, wherein the septum divides the tube into two portions, wherein the septum is connected to the stepped twist insert.   
     
     
         8 . The DFBAA of  claim 1 , further comprising:
 a bore defined by the HB circular waveguide antenna, wherein the bore has a frontal portion and a rear portion; and   an aperture plug at or near the frontal portion of the bore of the HB circular waveguide antenna.   
     
     
         9 . The DFBAA of  claim 1 , further comprising:
 a throat of the LB quad-ridge antenna defined between four ridges; and   a non-conductive disc that covers the throat, wherein the non-conductive disc has an outer perimeter that is similar to a portion of the radiator, and wherein the outer perimeter of the non-conductive disc is interrupted by at least four cutouts that complement the four ridges of the LB quad-ridge antenna.   
     
     
         10 . The DFBAA of  claim 9 , further comprising:
 a flat frontal surface of the non-conductive disc; and   a flat rear surface of the non-conductive disc.   
     
     
         11 . The DFBAA assembly of  claim 1 , further comprising:
 a bore defined by the HB circular waveguide antenna, wherein the bore has a frontal portion and a rear portion; and   a choke located at or near the frontal portion of the bore.   
     
     
         12 . The DFBAA of  claim 1 , further comprising:
 a radome having an end that abuts or is closely adjacent to the ledge, wherein the radome covers the LB quad-ridge antenna and the HB circular waveguide antenna; and   wherein the radome is frustoconical in configuration defining a flat frontal wall of the radome, wherein a thickness of the flat frontal wall of the radome is measured from a front surface to a rear surface of the flat frontal wall and the thickness is in a range from 0.005 inch to 0.05 inch.